All Questions
Tagged with gate-synthesis programming
17 questions
1
vote
1
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255
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Simple successor gate
I want to create a gate that, given a sequence of qbits that encode n, transforms that sequence in n+1, in other words the successor function. I managed to do it in qiskit by writing this:
...
- 113
0
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0
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46
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BQSkit Selecting Starting Circuit Structure
Background
On the BQSKit repository, there is a nice example of using the qfactor algorithm to instantiate a 3-qubit Toffoli circuit. For this to work, however, it is first necessary to specify an ...
- 197
2
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1
answer
80
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Consecutive phased X rotation gates simplification
I have two consecutive phased X rotation (see cirq PhasedXPowGate gate definition), how to find both t' and p' angles (according to previoux cirq definition) so that two consecutive PhasedXPowGate are ...
- 451
2
votes
1
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104
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Converting a Matrix to a Gate in OpenQasm 2
I am a beginner when it comes to quantum computing so forgive me if this is a dumb question. Does anyone know how to create a gate from any matrix on OpenQasm2? Specifically, can anyone provide any ...
- 31
1
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0
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180
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PyZX optimisation steps for Clifford circuits
Given the following ZX-diagram
It should represent some random Clifford circuit (LC means Local Clifford).
As far as I got, any Clifford circuit can be transformed into a ZX-diagram like the above, i....
- 2,058
4
votes
0
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139
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How exactly does the QuantumCircuit.decompose() method work?
From what I can understand from the source code, the circuit is converted into a DAG before the decomposition transpiler is performed onto the DAG circuit.
How does converting to a DAG circuit help us ...
- 103
10
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2
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2k
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Transpilation into custom gate set in qiskit
In qiskit, I can transpile a given circuit into a some predefined gate set as follows (just an example)
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- 1,695
2
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1
answer
159
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How does MCPhaseGate/MCU1Gate works internally in qiskit?
I was curious about the implementation of MCPhase/MCU1Gate and how it works without ancilla qubits. I ended up checking the code of the some auxiliary (?) function ...
- 61
1
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1
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2k
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How to code a projector operator in qiskit?
I'm new to qiskit and I want to know how do I define a projector operator in qiskit? Specifically, I have prepared a 3 qubit system, and after applying a whole lot of gates and measuring it in a state ...
- 319
2
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1
answer
1k
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Principal square root of Pauli Y gate in Qiskit?
I've seen a similar question asked (How do I compute the square root of the $Y$ gate?) but I'm trying to understand how I can use the gates $Y^{\frac{1}{2}}$ or $Y^{\frac{1}{4}}$ in Qiskit in terms of ...
- 131
2
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1
answer
801
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Building an N-qubit Controlled S Gate
I've been beating my head against this problem for three days now and I just can't seem to crack it. To construct an N-qubit controlled Unitary gate, I can do something like this (note I'm using ...
- 351
33
votes
6
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15k
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How do I build a gate from a matrix on Qiskit?
I'm creating a gate for a project and need to test if it has the same results as the original circuit in a simulator, how do I build this gate on Qiskit? It's a 3 qubit gate, 8x8 matrix:
$$
\frac{1}{...
- 775
3
votes
2
answers
421
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Implementing gate with two parameters using Qiskit in Python
I am trying to implement the HHL algorithm (for solving $Ax=b$). I am assuming $A$ to be unitary and Hermitian so that I can find the Hamiltonian simulation for it easily.
For any $A$ to be Hermitian ...
- 185
6
votes
2
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1k
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Measuring the Hamiltonian in the VQE
I am trying to implement VQE in pyQuil and am dumbfounded by how to measure the expectation value of a general Hamiltonian on $\mathbb{C}^{2^n}$ i.e. determine $\langle\psi , H \psi\rangle$ on a ...
13
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2
answers
2k
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Automatic compilation of quantum circuits
A recent question here asked how to compile the 4-qubit gate CCCZ (controlled-controlled-controlled-Z) into simple 1-qubit and 2-qubit gates, and the only answer given so far requires 63 gates!
The ...
6
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2
answers
701
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How do we code the matrix for a controlled operation knowing the control qubit, the target qubit and the $2\times 2$ unitary?
Having n qubits, I want to have the unitary described a controlled operation.
Say for example you get as input a unitary, an index for a controlled qubit and another for a target.
How would you code ...
- 4,774
8
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2
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692
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Construct Controlled-$G^{\dagger}$ from known Controlled-$G$
Let there be a known a scheme (quantum circuit) of Controlled-G, where unitary gate G has G$^†$ such that G≠G$^†$ and GG$^†$=I (for example S and S$^†$, T and T$^†$, V and V$^†$, but not Pauli and H ...
